Many products are often manufactured in a continuous web format for the processing efficiencies and capabilities that can be achieved with that approach. The term “web” is used herein to describe thin materials which are manufactured or processed in continuous, flexible strip form. Illustrative examples include thin plastics, paper, textiles, metals, and composites of such materials.
Such operations typically entail use of one or more, frequently many more, rollers around which the web is conveyed throughout a series of treatments, manufacturing steps, etc. Rollers are used for many purposes, including, for example, unwinding a wound roll of the web material, turning the direction of the web, applying pressure to the web in nip stations, positioning the web for travel through coating and other treatment stations, positioning multiple webs for lamination, stretching webs, etc., and winding up a roll of the web material. Webs can develop large static charges during unwinding or winding of rolls, as well as while passing over rollers in a web processing line. The strong electrostatic fields associated with these charges can cause surface contamination of the webs by attracting dust particles, fibers, bugs, hair, processing debris, and the like. A large static charge residing on a wound roll can also present a safety hazard. It is often necessary to use alarmed devices to keep human operators out of the areas of unwinding stations and winders for their safety.
Existing methods for eliminating static charge on a wound roll have drawbacks. Ionized air is often blown into winder or unwind station areas. This has some beneficial effect, but does not greatly diminish static charge, and in the act of blowing air toward the web, dust, debris, and the like may be brought into proximity of the static-charged web which would not otherwise be so introduced. So-called “static string” products are also often used. They are also limited in their effect, and require precise spacing from the charged web in order to maximize their effect. An apparatus and technique are needed to reliably reduce static electricity generated on polymeric film.
Many products are manufactured by thermoforming, or by injection molding, or by conversion of web materials via die-cutting or laser-cutting or the like, or are otherwise produced in such a manner as to provide a discrete shaped part. Such shaped parts may develop and bear a large static charge as a result of handling, forming, or converting processes. The strong electrostatic fields associated with these charges can cause surface contamination of the shaped parts by attracting dust particles, fibers, bugs, hair, processing debris, and the like. A large static charge residing on a shaped part can also present a safety hazard.
Existing methods for eliminating static charge on shaped parts have drawbacks. An apparatus and technique are needed to reliably reduce static electricity generated on polymeric shaped parts.